Paper controller for image forming apparatus

ABSTRACT

A paper controller of an image forming apparatus includes a machine base having a main passage and a bypass therein. Three conveying rollers are pivoted on the machine to send papers going through the main passage and the bypass respectively. One conveying roller adjacent to the paper outlet has a driving portion and a driving-free portion, which is a flat face on the circumference, that the driving portion touches a driven roller to make it rotating and the driving-free portion will not touch the driven roller when the conveying roller is rotating that a gap is formed between the driving-free portion and the driven roller to prevent the paper from jamming at the paper outlet.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an office machine, and more particularly to a paper controller of an image forming apparatus.

2. Description of the Related Art

When an image forming apparatus, such as copy machine, scanner, printer, and other office machines, is doing double-sided scanning or double-sided printing, papers occasionally overlap and jam during the process of feeding papers. To overcome this problem, Taiwan utility model patent No. M291574 provides a paper control device which includes a linkage mechanism to separate an idler at a paper outlet from an outputting roller. It prevents the overlapped papers from jam in a double-sided scanning or double-sided printing work. U.S. Pat. No. 5,784,680 provides another device having a paw to switch paper passages that the paper inlet and the paper outlet are located at different passages in double-sided scanning or double-sided printing to overcome the jam problem.

However, the above patents provide complex structures that the costs of such devices are very high and they are difficult to maintain and repair.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a paper controller for an image forming apparatus to overcome the paper jam problem with a simple structure.

To meet the primary objective, a paper controller of the present invention includes a machine base having a paper passage therein, and the paper passage including a main passage and a bypass, wherein opposite ends of the main passage are connected to a paper inlet and a paper outlet of the machine base respectively and opposite ends of the bypass are connected to the main passage and one of the end of the bypass is close to the paper outlet; a first conveying roller pivoted on the machine base and having a portion received in the main passage; a driven roller pivoted on the machine and having a portion received in the main passage, wherein the driven roller is closer to the paper outlet than the end of the bypass; and a second conveying roller pivoted on the machine base and having a portion received in the main passage and association with the driven roller, wherein the second conveying roller has a driving-free portion and a driving portion, and a distance between the driving portion and a center of the second conveying roller is greater than a distance between the driving-free portion and the center of the second conveying roller that when the second conveying roller rotates, the driving portion touches the driven roller and there is a gap between the driving-free portion and driven roller.

In accordance with the ideas above, the paper will not jam at the paper outlet during a double-sided scanning.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a first preferred embodiment of the present invention;

FIG. 2 is a partially sectional view of the first preferred embodiment of the present invention;

FIG. 3 shows the second conveying roller having a convex face;

FIG. 4 shows the second conveying roller having a concave face;

FIG. 5 shows the first paper location sensor;

FIG. 6 shows the second paper location sensor;

FIG. 7 shows the roller sensor;

FIG. 8 to FIG. 13 are sketch diagrams, showing the actions of the first preferred embodiment of the present invention; and

FIG. 14 is a sectional view of a second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, an image forming apparatus 100 of the first preferred embodiment of the present invention includes a scanning device 1 and a paper controller 2. The scanning device 1 scans a paper and forms electromagnetic data. The paper controller 2 is provided on the scanning device 1 and includes a machine base 10, a paper feeder 20, a first conveying roller 30, a second conveying roller 40, a third conveying roller 50, a controlling device 60, a first paper location sensor 70, a second paper location sensor 75, and a roller sensor 80.

The machine base 10 has a paper passage 11 therein for papers to pass therethrough. The passage 11 has a main passage 111 and a bypass 112. The main passage 111 has a start end 111 a and a tail end 111 b. The start end 111 a is out of the machine base 10 to form a paper inlet 12, and the tail end 111 b is out of the machine base 10 also to form a paper outlet 13. The scanning device 1 has a scanning point S which is located at a halfway of the main passage 111 to scan the paper passing through the main passage 111. The bypass 111 b has an end connected to the main passage 111 between the start end 111 a and the tail end 111 b and the other end connected to the paper outlet 13.

The paper feeder 20 is provided at the paper inlet 12 of the machine base 10 and has a pre-feeding roller 21 and a feeding roller 22. The pre-feeding roller 21 conveys the paper at the paper inlet 12 forward the main passage 111 in sequence, and after that the feeding roller 22 keeps conveying the paper into the main passage 111.

The first conveying roller 30 is pivoted on the machine base 10 in the main passage 111 between the start end 111 a and the scanning point S. A driven roller 91 is provided in the main passage 111 in association with the first conveying roller 30. The driven roller 91 touches the first conveying roller 30 to convey the paper, after the feeding roller 22, to the scanning point S and the paper outlet 13.

The third conveying roller 50 is pivoted on the machine base 10 in the main passage 111 adjacent to the tail end 111 b and between the ends of the bypass 112. A driven roller 92 is provided in the bypass 112 in association with the third conveying roller 50. The driven roller 92 touches the third conveying roller 50 to convey the paper in the bypass 112 into the main passage 111. A driven roller 93 is provided in the main passage 111 in association with the third conveying roller 50. The driven roller 93 touches the third conveying roller 50 to convey the paper in the main passage 111 to the paper outlet 13.

As shown in FIG. 2, a driven roller 94 is provided in the main passage 111 adjacent to the paper outlet 13 and in association with the second conveying roller 40. The driven roller 94 touches the second conveying roller 40 to convey paper out of the paper outlet 13 or convey the paper from the paper outlet 13 to the bypass 112. The difference between the second conveying roller 40 and the other conveying rollers 30, 50 is that the second conveying roller 40 is not round, it has a flat portion (driving-free portion 41). A distance between a center of the second conveying roller 40 and the driving-free portion 41 is shorter than a distance between the center and the other circumference (driving portion 42). Therefore, there is a gap intermittently formed between the second conveying roller 40 and the driven roller 94 when the second conveying roller 40 is running. In the present embodiment, the surface portion is flat, however it may be a roller 45 with a convex gap face as shown in FIG. 3 or a roller 46 with concave gap face as shown in FIG. 4, or other forms with the character of a portion of the surface having a shorter diameter.

A perimeter of the driving portion 42 of the second conveying roller 40 is greater than a distance L of the bypass 112 between the second conveying roller 40 and the third conveying roller 50 that the third conveying roller 50 may touch the paper from the second conveying roller 40 before the second conveying roller 40 touches the paper because the driving-free portion 41 of the second conveying roller 40 faces the driven wheel 94.

The controlling device 60 is provided on the machine base 10 to control the rollers 21, 22 and the conveying rollers 30, 40, 50.

The first paper position sensor 70 is provided on the machine base 10 beside the paper inlet 12. As shown in FIG. 5, in the present invention, the first paper position sensor 70 has a light emitter 71 and a light receiver 72 that the light emitter 71 emits light to the light receiver 72. The light of the light emitter 71 will be cut off when a paper is put in the paper inlet 12 that a signal is transmitted to the controlling device 60 when the paper is ready and it may start the paper feeder 20 to send the paper into the paper passage 11.

The second paper location sensor 75 is provided on the machine base 10 in the main passage 111. As shown in FIG. 6, in the present invention, the second paper location sensor 75 has a light emitter 76 and a light receiver 77 that the light emitter 76 emits light to the light receiver 77. The light of the light emitter 76 will be cut off when a paper is passing through therebetween that a signal is transmitted to the controlling device 60 when the paper is in position and it may start the scanning device 1.

In addition, a preferred location of the second paper location sensor 75 is between the paper inlet 12 and the first conveying roller 30 and close to the first conveying roller 30. The second paper location sensor 75 senses the paper's location and starts the first conveying roller 30 for de-skew of the paper when the paper arrives the first conveying roller 30. In practice, the first and second paper location sensor 70, 75 may be replaced by optical switches or other relative devices.

The roller sensor 80 is provided on the base 10 and is at the tail end 111 b of the main passage 111. As shown in FIG. 7, in the present invention, the roller sensor 80 has a disk 81, a light emitter 82, and a light receiver 83. The disk 81 is provided on an axle of the second conveying roller 40 and has a gap 811 thereon. The light emitter 82 and the light receiver 83 are at opposite sides of the disk 81 that the light receiver 83 may receive the light from the light emitter 82 when the gap 811 of the disk 81 is right between the light emitter 82 and the light receiver 83 while the second conveying roller 40 is rotating. In other words, the roller sensor 80 may provide intermittent signals to the controlling device 60 to tell the position of the driving-free portion 41 of the second conveying roller 40. The controlling device 60 will stop the second conveying roller 40 when the driving-free portion 41 faces the driven roller 94. In practice, the roller sensor 80 may be replaced by reed switch, micro-switch, or other relative devices.

As shown in FIG. 8 to FIG. 13, in a procedure of scanning double sides of a paper, so called double-sided scanning, the paper feeder 20 sends the paper P into the main passage 111 when the first paper location sensor 70 detects a piece of paper arriving at the paper inlet 12, and then the scanning device 1 is started to scan the paper P when the second paper location sensor 75 detects a front P1 of the paper P (FIG. 8). The second conveying roller 40 is started for a clockwise rotation and the third conveying roller 50 is started for a counterclockwise rotation to send the paper P toward the paper outlet 13 when a rear P2 of the paper P leaves the second paper location sensor 75 (FIG. 9). After the paper P leaves the third conveying roller 50, as shown in FIG. 10, the second conveying roller 40 is started for a counterclockwise rotation to send the paper P into the bypass 112 from the paper outlet 13. When the paper P goes into the bypass 112, the controlling device 60 stops the second conveying roller 40 according to the roller sensor 80, as shown in FIG. 11. When the second conveying roller 40 stops, the driving-free portion 41 of the second conveying roller 40 faces the driven roller 94 that there is a gap between the second conveying roller 40 and the driven roller 94. At the same time, the third conveying roller 50 keeps counterclockwise rotation to send the paper P to the main passage 111 for the second scanning. As the rear P2 of the paper P is moved out of the paper outlet 13 and the front P1 of the paper P has not entered the paper outlet 13 yet, the paper P has the front P1 and the rear P2 overlapped at the paper outlet 13, as shown in FIG. 12. At this moment, the paper P is free to be moved by the third conveying roller 50 because of the gap between the second conveying roller 40 and the driven roller 94 to prevent the jam problem. As the scanning device 1 completes the second scanning, as shown in FIG. 13, the second conveying roller 40 is restarted for clockwise rotation to send the paper P out of the paper outlet 13.

After double-sided scanning, the paper P may be sent into the bypass 112 again from the paper outlet 13 without scanning to flip the paper P that the papers may be stacked as they are stacked before scanning.

For a single side scanning, the procedure is completed when the paper P is moved out of the paper outlet 13, as shown in FIG. 7 and FIG. 8, without having to send the paper P back into the bypass 112.

As shown in FIG. 14, a paper controller 3 of the second preferred embodiment of the present invention provides a first conveying roller 310 serving both functions of sending paper in a main passage 331 to a paper outlet 330 and sending paper in a bypass 332 to the main passage 331. The action of the first conveying roller 310 will not affect a second conveying roller 320. It is clear that only two conveying rollers are needed in the paper controller 3 of the second preferred embodiment not three as above.

The description above is a few preferred embodiments of the present invention and the equivalence of the present invention is still in the scope of claim construction of the present invention. 

What is claimed is:
 1. A paper controller of an image forming apparatus, comprising: a machine base having a paper passage therein, and the paper passage including a main passage and a bypass, wherein opposite ends of the main passage are connected to a paper inlet and a paper outlet of the machine base respectively and opposite ends of the bypass are connected to the main passage and one of the end of the bypass is close to the paper outlet; a first conveying roller pivoted on the machine base and having a portion received in the main passage; a driven roller pivoted on the machine and having a portion received in the main passage, wherein the driven roller is closer to the paper outlet than the end of the bypass; and a second conveying roller pivoted on the machine base and having a portion received in the main passage and association with the driven roller, wherein the second conveying roller has a driving-free portion and a driving portion, and a distance between the driving portion and a center of the second conveying roller is greater than a distance between the driving-free portion and the center of the second conveying roller that when the second conveying roller rotates, the driving portion touches the driven roller and there is a gap between the driving-free portion and driven roller.
 2. The paper controller as defined in claim 1, further comprising a third conveying roller pivoted on the machine base and having portions received in the main passage and in the bypass respectively, and a length of the driving portion of the second conveying roller is greater than a distance in the bypass between the second conveying roller and the third conveying roller.
 3. The paper controller as defined in claim 1, further comprising paper feeder provided on the machine base which includes a pre-feeding roller to move papers at the paper inlet toward the main passage in sequence and a feeding roller behind the pre-feeding roller to move the papers into the main passage in sequence.
 4. The paper controller as defined in claim 1, further comprising a controlling device to control the first and second conveying rollers to rotating in a predetermined direction and stop them and a roller sensor to sense a position of the driving-free portion of the second conveying roller.
 5. The paper controller as defined in claim 1, further comprising a controlling device to control the first and second conveying rollers to rotating in a predetermined direction and stop them, and a paper location sensor to sense a location of the paper in the passage.
 6. The paper controller as defined in claim 1, further comprising a controlling device to control the first and second conveying rollers to rotating in a predetermined direction and stop them, and a paper location sensor to sense the paper at the paper inlet.
 7. The paper controller as defined in claim 4, wherein the roller sensor includes a disk with a gap provided on an axle of the second conveying roller, and a light emitter and a light receiver at opposite sides of the disk.
 8. The paper controller as defined in claim 1, wherein the driving-free portion of the second conveying roller has a flat face.
 9. The paper controller as defined in claim 1, wherein the driving-free portion of the second conveying roller has a convex face.
 10. The paper controller as defined in claim 1, wherein the driving-free portion of the second conveying roller has a concave face. 